622 lines
24 KiB
HTML
622 lines
24 KiB
HTML
<?xml version="1.0" encoding="utf-8" ?>
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<meta name="generator" content="Docutils 0.4: http://docutils.sourceforge.net/" />
|
|
<title>Indirect Iterator</title>
|
|
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
|
|
<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
|
|
<meta name="date" content="2004-11-01" />
|
|
<meta name="copyright" content="Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003." />
|
|
<style type="text/css">
|
|
|
|
/*
|
|
:Author: David Goodger
|
|
:Contact: goodger@users.sourceforge.net
|
|
:Date: $Date$
|
|
:Revision: $Revision$
|
|
:Copyright: This stylesheet has been placed in the public domain.
|
|
|
|
Default cascading style sheet for the HTML output of Docutils.
|
|
|
|
See http://docutils.sf.net/docs/howto/html-stylesheets.html for how to
|
|
customize this style sheet.
|
|
*/
|
|
|
|
/* used to remove borders from tables and images */
|
|
.borderless, table.borderless td, table.borderless th {
|
|
border: 0 }
|
|
|
|
table.borderless td, table.borderless th {
|
|
/* Override padding for "table.docutils td" with "! important".
|
|
The right padding separates the table cells. */
|
|
padding: 0 0.5em 0 0 ! important }
|
|
|
|
.first {
|
|
/* Override more specific margin styles with "! important". */
|
|
margin-top: 0 ! important }
|
|
|
|
.last, .with-subtitle {
|
|
margin-bottom: 0 ! important }
|
|
|
|
.hidden {
|
|
display: none }
|
|
|
|
a.toc-backref {
|
|
text-decoration: none ;
|
|
color: black }
|
|
|
|
blockquote.epigraph {
|
|
margin: 2em 5em ; }
|
|
|
|
dl.docutils dd {
|
|
margin-bottom: 0.5em }
|
|
|
|
/* Uncomment (and remove this text!) to get bold-faced definition list terms
|
|
dl.docutils dt {
|
|
font-weight: bold }
|
|
*/
|
|
|
|
div.abstract {
|
|
margin: 2em 5em }
|
|
|
|
div.abstract p.topic-title {
|
|
font-weight: bold ;
|
|
text-align: center }
|
|
|
|
div.admonition, div.attention, div.caution, div.danger, div.error,
|
|
div.hint, div.important, div.note, div.tip, div.warning {
|
|
margin: 2em ;
|
|
border: medium outset ;
|
|
padding: 1em }
|
|
|
|
div.admonition p.admonition-title, div.hint p.admonition-title,
|
|
div.important p.admonition-title, div.note p.admonition-title,
|
|
div.tip p.admonition-title {
|
|
font-weight: bold ;
|
|
font-family: sans-serif }
|
|
|
|
div.attention p.admonition-title, div.caution p.admonition-title,
|
|
div.danger p.admonition-title, div.error p.admonition-title,
|
|
div.warning p.admonition-title {
|
|
color: red ;
|
|
font-weight: bold ;
|
|
font-family: sans-serif }
|
|
|
|
/* Uncomment (and remove this text!) to get reduced vertical space in
|
|
compound paragraphs.
|
|
div.compound .compound-first, div.compound .compound-middle {
|
|
margin-bottom: 0.5em }
|
|
|
|
div.compound .compound-last, div.compound .compound-middle {
|
|
margin-top: 0.5em }
|
|
*/
|
|
|
|
div.dedication {
|
|
margin: 2em 5em ;
|
|
text-align: center ;
|
|
font-style: italic }
|
|
|
|
div.dedication p.topic-title {
|
|
font-weight: bold ;
|
|
font-style: normal }
|
|
|
|
div.figure {
|
|
margin-left: 2em ;
|
|
margin-right: 2em }
|
|
|
|
div.footer, div.header {
|
|
clear: both;
|
|
font-size: smaller }
|
|
|
|
div.line-block {
|
|
display: block ;
|
|
margin-top: 1em ;
|
|
margin-bottom: 1em }
|
|
|
|
div.line-block div.line-block {
|
|
margin-top: 0 ;
|
|
margin-bottom: 0 ;
|
|
margin-left: 1.5em }
|
|
|
|
div.sidebar {
|
|
margin-left: 1em ;
|
|
border: medium outset ;
|
|
padding: 1em ;
|
|
background-color: #ffffee ;
|
|
width: 40% ;
|
|
float: right ;
|
|
clear: right }
|
|
|
|
div.sidebar p.rubric {
|
|
font-family: sans-serif ;
|
|
font-size: medium }
|
|
|
|
div.system-messages {
|
|
margin: 5em }
|
|
|
|
div.system-messages h1 {
|
|
color: red }
|
|
|
|
div.system-message {
|
|
border: medium outset ;
|
|
padding: 1em }
|
|
|
|
div.system-message p.system-message-title {
|
|
color: red ;
|
|
font-weight: bold }
|
|
|
|
div.topic {
|
|
margin: 2em }
|
|
|
|
h1.section-subtitle, h2.section-subtitle, h3.section-subtitle,
|
|
h4.section-subtitle, h5.section-subtitle, h6.section-subtitle {
|
|
margin-top: 0.4em }
|
|
|
|
h1.title {
|
|
text-align: center }
|
|
|
|
h2.subtitle {
|
|
text-align: center }
|
|
|
|
hr.docutils {
|
|
width: 75% }
|
|
|
|
img.align-left {
|
|
clear: left }
|
|
|
|
img.align-right {
|
|
clear: right }
|
|
|
|
ol.simple, ul.simple {
|
|
margin-bottom: 1em }
|
|
|
|
ol.arabic {
|
|
list-style: decimal }
|
|
|
|
ol.loweralpha {
|
|
list-style: lower-alpha }
|
|
|
|
ol.upperalpha {
|
|
list-style: upper-alpha }
|
|
|
|
ol.lowerroman {
|
|
list-style: lower-roman }
|
|
|
|
ol.upperroman {
|
|
list-style: upper-roman }
|
|
|
|
p.attribution {
|
|
text-align: right ;
|
|
margin-left: 50% }
|
|
|
|
p.caption {
|
|
font-style: italic }
|
|
|
|
p.credits {
|
|
font-style: italic ;
|
|
font-size: smaller }
|
|
|
|
p.label {
|
|
white-space: nowrap }
|
|
|
|
p.rubric {
|
|
font-weight: bold ;
|
|
font-size: larger ;
|
|
color: maroon ;
|
|
text-align: center }
|
|
|
|
p.sidebar-title {
|
|
font-family: sans-serif ;
|
|
font-weight: bold ;
|
|
font-size: larger }
|
|
|
|
p.sidebar-subtitle {
|
|
font-family: sans-serif ;
|
|
font-weight: bold }
|
|
|
|
p.topic-title {
|
|
font-weight: bold }
|
|
|
|
pre.address {
|
|
margin-bottom: 0 ;
|
|
margin-top: 0 ;
|
|
font-family: serif ;
|
|
font-size: 100% }
|
|
|
|
pre.literal-block, pre.doctest-block {
|
|
margin-left: 2em ;
|
|
margin-right: 2em ;
|
|
background-color: #eeeeee }
|
|
|
|
span.classifier {
|
|
font-family: sans-serif ;
|
|
font-style: oblique }
|
|
|
|
span.classifier-delimiter {
|
|
font-family: sans-serif ;
|
|
font-weight: bold }
|
|
|
|
span.interpreted {
|
|
font-family: sans-serif }
|
|
|
|
span.option {
|
|
white-space: nowrap }
|
|
|
|
span.pre {
|
|
white-space: pre }
|
|
|
|
span.problematic {
|
|
color: red }
|
|
|
|
span.section-subtitle {
|
|
/* font-size relative to parent (h1..h6 element) */
|
|
font-size: 80% }
|
|
|
|
table.citation {
|
|
border-left: solid 1px gray;
|
|
margin-left: 1px }
|
|
|
|
table.docinfo {
|
|
margin: 2em 4em }
|
|
|
|
table.docutils {
|
|
margin-top: 0.5em ;
|
|
margin-bottom: 0.5em }
|
|
|
|
table.footnote {
|
|
border-left: solid 1px black;
|
|
margin-left: 1px }
|
|
|
|
table.docutils td, table.docutils th,
|
|
table.docinfo td, table.docinfo th {
|
|
padding-left: 0.5em ;
|
|
padding-right: 0.5em ;
|
|
vertical-align: top }
|
|
|
|
table.docutils th.field-name, table.docinfo th.docinfo-name {
|
|
font-weight: bold ;
|
|
text-align: left ;
|
|
white-space: nowrap ;
|
|
padding-left: 0 }
|
|
|
|
h1 tt.docutils, h2 tt.docutils, h3 tt.docutils,
|
|
h4 tt.docutils, h5 tt.docutils, h6 tt.docutils {
|
|
font-size: 100% }
|
|
|
|
tt.docutils {
|
|
background-color: #eeeeee }
|
|
|
|
ul.auto-toc {
|
|
list-style-type: none }
|
|
|
|
</style>
|
|
</head>
|
|
<body>
|
|
<div class="document" id="indirect-iterator">
|
|
<h1 class="title">Indirect Iterator</h1>
|
|
<table class="docinfo" frame="void" rules="none">
|
|
<col class="docinfo-name" />
|
|
<col class="docinfo-content" />
|
|
<tbody valign="top">
|
|
<tr><th class="docinfo-name">Author:</th>
|
|
<td>David Abrahams, Jeremy Siek, Thomas Witt</td></tr>
|
|
<tr><th class="docinfo-name">Contact:</th>
|
|
<td><a class="first reference" href="mailto:dave@boost-consulting.com">dave@boost-consulting.com</a>, <a class="reference" href="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</a>, <a class="last reference" href="mailto:witt@ive.uni-hannover.de">witt@ive.uni-hannover.de</a></td></tr>
|
|
<tr><th class="docinfo-name">Organization:</th>
|
|
<td><a class="first reference" href="http://www.boost-consulting.com">Boost Consulting</a>, Indiana University <a class="reference" href="http://www.osl.iu.edu">Open Systems
|
|
Lab</a>, University of Hanover <a class="last reference" href="http://www.ive.uni-hannover.de">Institute for Transport
|
|
Railway Operation and Construction</a></td></tr>
|
|
<tr><th class="docinfo-name">Date:</th>
|
|
<td>2004-11-01</td></tr>
|
|
<tr><th class="docinfo-name">Copyright:</th>
|
|
<td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003.</td></tr>
|
|
</tbody>
|
|
</table>
|
|
<!-- Distributed under the Boost -->
|
|
<!-- Software License, Version 1.0. (See accompanying -->
|
|
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">abstract:</th><td class="field-body"><!-- Copyright David Abrahams 2006. Distributed under the Boost -->
|
|
<!-- Software License, Version 1.0. (See accompanying -->
|
|
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
|
|
<tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> adapts an iterator by applying an
|
|
<em>extra</em> dereference inside of <tt class="docutils literal"><span class="pre">operator*()</span></tt>. For example, this
|
|
iterator adaptor makes it possible to view a container of pointers
|
|
(e.g. <tt class="docutils literal"><span class="pre">list<foo*></span></tt>) as if it were a container of the pointed-to type
|
|
(e.g. <tt class="docutils literal"><span class="pre">list<foo></span></tt>). <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> depends on two
|
|
auxiliary traits, <tt class="docutils literal"><span class="pre">pointee</span></tt> and <tt class="docutils literal"><span class="pre">indirect_reference</span></tt>, to
|
|
provide support for underlying iterators whose <tt class="docutils literal"><span class="pre">value_type</span></tt> is
|
|
not an iterator.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="contents topic">
|
|
<p class="topic-title first"><a id="table-of-contents" name="table-of-contents">Table of Contents</a></p>
|
|
<ul class="simple">
|
|
<li><a class="reference" href="#indirect-iterator-synopsis" id="id2" name="id2"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> synopsis</a></li>
|
|
<li><a class="reference" href="#indirect-iterator-requirements" id="id3" name="id3"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> requirements</a></li>
|
|
<li><a class="reference" href="#indirect-iterator-models" id="id4" name="id4"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> models</a></li>
|
|
<li><a class="reference" href="#indirect-iterator-operations" id="id5" name="id5"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> operations</a></li>
|
|
<li><a class="reference" href="#example" id="id6" name="id6">Example</a></li>
|
|
</ul>
|
|
</div>
|
|
<div class="section">
|
|
<h1><a class="toc-backref" href="#id2" id="indirect-iterator-synopsis" name="indirect-iterator-synopsis"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> synopsis</a></h1>
|
|
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
|
|
<!-- Software License, Version 1.0. (See accompanying -->
|
|
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
|
|
<pre class="literal-block">
|
|
template <
|
|
class Iterator
|
|
, class Value = use_default
|
|
, class CategoryOrTraversal = use_default
|
|
, class Reference = use_default
|
|
, class Difference = use_default
|
|
>
|
|
class indirect_iterator
|
|
{
|
|
public:
|
|
typedef /* see below */ value_type;
|
|
typedef /* see below */ reference;
|
|
typedef /* see below */ pointer;
|
|
typedef /* see below */ difference_type;
|
|
typedef /* see below */ iterator_category;
|
|
|
|
indirect_iterator();
|
|
indirect_iterator(Iterator x);
|
|
|
|
template <
|
|
class Iterator2, class Value2, class Category2
|
|
, class Reference2, class Difference2
|
|
>
|
|
indirect_iterator(
|
|
indirect_iterator<
|
|
Iterator2, Value2, Category2, Reference2, Difference2
|
|
> const& y
|
|
, typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition
|
|
);
|
|
|
|
Iterator const& base() const;
|
|
reference operator*() const;
|
|
indirect_iterator& operator++();
|
|
indirect_iterator& operator--();
|
|
private:
|
|
Iterator m_iterator; // exposition
|
|
};
|
|
</pre>
|
|
<p>The member types of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> are defined according to
|
|
the following pseudo-code, where <tt class="docutils literal"><span class="pre">V</span></tt> is
|
|
<tt class="docutils literal"><span class="pre">iterator_traits<Iterator>::value_type</span></tt></p>
|
|
<pre class="literal-block">
|
|
if (Value is use_default) then
|
|
typedef remove_const<pointee<V>::type>::type value_type;
|
|
else
|
|
typedef remove_const<Value>::type value_type;
|
|
|
|
if (Reference is use_default) then
|
|
if (Value is use_default) then
|
|
typedef indirect_reference<V>::type reference;
|
|
else
|
|
typedef Value& reference;
|
|
else
|
|
typedef Reference reference;
|
|
|
|
if (Value is use_default) then
|
|
typedef pointee<V>::type* pointer;
|
|
else
|
|
typedef Value* pointer;
|
|
|
|
if (Difference is use_default)
|
|
typedef iterator_traits<Iterator>::difference_type difference_type;
|
|
else
|
|
typedef Difference difference_type;
|
|
|
|
if (CategoryOrTraversal is use_default)
|
|
typedef <em>iterator-category</em> (
|
|
iterator_traversal<Iterator>::type,``reference``,``value_type``
|
|
) iterator_category;
|
|
else
|
|
typedef <em>iterator-category</em> (
|
|
CategoryOrTraversal,``reference``,``value_type``
|
|
) iterator_category;
|
|
</pre>
|
|
</div>
|
|
<div class="section">
|
|
<h1><a class="toc-backref" href="#id3" id="indirect-iterator-requirements" name="indirect-iterator-requirements"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> requirements</a></h1>
|
|
<p>The expression <tt class="docutils literal"><span class="pre">*v</span></tt>, where <tt class="docutils literal"><span class="pre">v</span></tt> is an object of
|
|
<tt class="docutils literal"><span class="pre">iterator_traits<Iterator>::value_type</span></tt>, shall be valid
|
|
expression and convertible to <tt class="docutils literal"><span class="pre">reference</span></tt>. <tt class="docutils literal"><span class="pre">Iterator</span></tt> shall
|
|
model the traversal concept indicated by <tt class="docutils literal"><span class="pre">iterator_category</span></tt>.
|
|
<tt class="docutils literal"><span class="pre">Value</span></tt>, <tt class="docutils literal"><span class="pre">Reference</span></tt>, and <tt class="docutils literal"><span class="pre">Difference</span></tt> shall be chosen so
|
|
that <tt class="docutils literal"><span class="pre">value_type</span></tt>, <tt class="docutils literal"><span class="pre">reference</span></tt>, and <tt class="docutils literal"><span class="pre">difference_type</span></tt> meet
|
|
the requirements indicated by <tt class="docutils literal"><span class="pre">iterator_category</span></tt>.</p>
|
|
<p>[Note: there are further requirements on the
|
|
<tt class="docutils literal"><span class="pre">iterator_traits<Iterator>::value_type</span></tt> if the <tt class="docutils literal"><span class="pre">Value</span></tt>
|
|
parameter is not <tt class="docutils literal"><span class="pre">use_default</span></tt>, as implied by the algorithm for
|
|
deducing the default for the <tt class="docutils literal"><span class="pre">value_type</span></tt> member.]</p>
|
|
</div>
|
|
<div class="section">
|
|
<h1><a class="toc-backref" href="#id4" id="indirect-iterator-models" name="indirect-iterator-models"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> models</a></h1>
|
|
<p>In addition to the concepts indicated by <tt class="docutils literal"><span class="pre">iterator_category</span></tt>
|
|
and by <tt class="docutils literal"><span class="pre">iterator_traversal<indirect_iterator>::type</span></tt>, a
|
|
specialization of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> models the following
|
|
concepts, Where <tt class="docutils literal"><span class="pre">v</span></tt> is an object of
|
|
<tt class="docutils literal"><span class="pre">iterator_traits<Iterator>::value_type</span></tt>:</p>
|
|
<blockquote>
|
|
<ul class="simple">
|
|
<li>Readable Iterator if <tt class="docutils literal"><span class="pre">reference(*v)</span></tt> is convertible to
|
|
<tt class="docutils literal"><span class="pre">value_type</span></tt>.</li>
|
|
<li>Writable Iterator if <tt class="docutils literal"><span class="pre">reference(*v)</span> <span class="pre">=</span> <span class="pre">t</span></tt> is a valid
|
|
expression (where <tt class="docutils literal"><span class="pre">t</span></tt> is an object of type
|
|
<tt class="docutils literal"><span class="pre">indirect_iterator::value_type</span></tt>)</li>
|
|
<li>Lvalue Iterator if <tt class="docutils literal"><span class="pre">reference</span></tt> is a reference type.</li>
|
|
</ul>
|
|
</blockquote>
|
|
<p><tt class="docutils literal"><span class="pre">indirect_iterator<X,V1,C1,R1,D1></span></tt> is interoperable with
|
|
<tt class="docutils literal"><span class="pre">indirect_iterator<Y,V2,C2,R2,D2></span></tt> if and only if <tt class="docutils literal"><span class="pre">X</span></tt> is
|
|
interoperable with <tt class="docutils literal"><span class="pre">Y</span></tt>.</p>
|
|
</div>
|
|
<div class="section">
|
|
<h1><a class="toc-backref" href="#id5" id="indirect-iterator-operations" name="indirect-iterator-operations"><tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> operations</a></h1>
|
|
<p>In addition to the operations required by the concepts described
|
|
above, specializations of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> provide the
|
|
following operations.</p>
|
|
<p><tt class="docutils literal"><span class="pre">indirect_iterator();</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">Iterator</span></tt> must be Default Constructible.</td>
|
|
</tr>
|
|
<tr class="field"><th class="field-name">Effects:</th><td class="field-body">Constructs an instance of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> with
|
|
a default-constructed <tt class="docutils literal"><span class="pre">m_iterator</span></tt>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><tt class="docutils literal"><span class="pre">indirect_iterator(Iterator</span> <span class="pre">x);</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Effects:</th><td class="field-body">Constructs an instance of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> with
|
|
<tt class="docutils literal"><span class="pre">m_iterator</span></tt> copy constructed from <tt class="docutils literal"><span class="pre">x</span></tt>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<pre class="literal-block">
|
|
template <
|
|
class Iterator2, class Value2, unsigned Access, class Traversal
|
|
, class Reference2, class Difference2
|
|
>
|
|
indirect_iterator(
|
|
indirect_iterator<
|
|
Iterator2, Value2, Access, Traversal, Reference2, Difference2
|
|
> const& y
|
|
, typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition
|
|
);
|
|
</pre>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="docutils literal"><span class="pre">Iterator2</span></tt> is implicitly convertible to <tt class="docutils literal"><span class="pre">Iterator</span></tt>.</td>
|
|
</tr>
|
|
<tr class="field"><th class="field-name">Effects:</th><td class="field-body">Constructs an instance of <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> whose
|
|
<tt class="docutils literal"><span class="pre">m_iterator</span></tt> subobject is constructed from <tt class="docutils literal"><span class="pre">y.base()</span></tt>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><tt class="docutils literal"><span class="pre">Iterator</span> <span class="pre">const&</span> <span class="pre">base()</span> <span class="pre">const;</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">m_iterator</span></tt></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><tt class="docutils literal"><span class="pre">reference</span> <span class="pre">operator*()</span> <span class="pre">const;</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">**m_iterator</span></tt></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><tt class="docutils literal"><span class="pre">indirect_iterator&</span> <span class="pre">operator++();</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Effects:</th><td class="field-body"><tt class="docutils literal"><span class="pre">++m_iterator</span></tt></td>
|
|
</tr>
|
|
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><tt class="docutils literal"><span class="pre">indirect_iterator&</span> <span class="pre">operator--();</span></tt></p>
|
|
<table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field"><th class="field-name">Effects:</th><td class="field-body"><tt class="docutils literal"><span class="pre">--m_iterator</span></tt></td>
|
|
</tr>
|
|
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="docutils literal"><span class="pre">*this</span></tt></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
|
|
<!-- Software License, Version 1.0. (See accompanying -->
|
|
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
|
|
</div>
|
|
<div class="section">
|
|
<h1><a class="toc-backref" href="#id6" id="example" name="example">Example</a></h1>
|
|
<p>This example prints an array of characters, using
|
|
<tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> to access the array of characters through an
|
|
array of pointers. Next <tt class="docutils literal"><span class="pre">indirect_iterator</span></tt> is used with the
|
|
<tt class="docutils literal"><span class="pre">transform</span></tt> algorithm to copy the characters (incremented by one) to
|
|
another array. A constant indirect iterator is used for the source and
|
|
a mutable indirect iterator is used for the destination. The last part
|
|
of the example prints the original array of characters, but this time
|
|
using the <tt class="docutils literal"><span class="pre">make_indirect_iterator</span></tt> helper function.</p>
|
|
<pre class="literal-block">
|
|
char characters[] = "abcdefg";
|
|
const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
|
|
char* pointers_to_chars[N]; // at the end.
|
|
for (int i = 0; i < N; ++i)
|
|
pointers_to_chars[i] = &characters[i];
|
|
|
|
// Example of using indirect_iterator
|
|
|
|
boost::indirect_iterator<char**, char>
|
|
indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
|
|
|
|
std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
|
|
std::cout << std::endl;
|
|
|
|
|
|
// Example of making mutable and constant indirect iterators
|
|
|
|
char mutable_characters[N];
|
|
char* pointers_to_mutable_chars[N];
|
|
for (int j = 0; j < N; ++j)
|
|
pointers_to_mutable_chars[j] = &mutable_characters[j];
|
|
|
|
boost::indirect_iterator<char* const*> mutable_indirect_first(pointers_to_mutable_chars),
|
|
mutable_indirect_last(pointers_to_mutable_chars + N);
|
|
boost::indirect_iterator<char* const*, char const> const_indirect_first(pointers_to_chars),
|
|
const_indirect_last(pointers_to_chars + N);
|
|
|
|
std::transform(const_indirect_first, const_indirect_last,
|
|
mutable_indirect_first, std::bind1st(std::plus<char>(), 1));
|
|
|
|
std::copy(mutable_indirect_first, mutable_indirect_last,
|
|
std::ostream_iterator<char>(std::cout, ","));
|
|
std::cout << std::endl;
|
|
|
|
|
|
// Example of using make_indirect_iterator()
|
|
|
|
std::copy(boost::make_indirect_iterator(pointers_to_chars),
|
|
boost::make_indirect_iterator(pointers_to_chars + N),
|
|
std::ostream_iterator<char>(std::cout, ","));
|
|
std::cout << std::endl;
|
|
</pre>
|
|
<p>The output is:</p>
|
|
<pre class="literal-block">
|
|
a,b,c,d,e,f,g,
|
|
b,c,d,e,f,g,h,
|
|
a,b,c,d,e,f,g,
|
|
</pre>
|
|
<p>The source code for this example can be found <a class="reference" href="../example/indirect_iterator_example.cpp">here</a>.</p>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|